A conventional daylighting structure that intakes an incident sunlight from a window part, to an indoor ceiling surface by a reflection effect in an upper surface of a light shelf attached to an outside of a building window part in a horizontal state, has been suggested (for example, Patent Document 1 described below).
In this daylighting structure, a plurality of prism surface materials are placed side by side in a vertical direction in an upper inside of the building window part. Thereby, generally, a summer-time daylight is reflected to the outside and spring-time, autumn-time, and winter-time daylights are refracted to an indoor upper space region including the ceiling surface.